<!DOCTYPE html>
<html>
    <script src="./预加载.js"></script>
    <script>
        function imgLoaded(){
            console.log(this.width);
            // document.body.appendChild(this);
        }
    </script>
    <body>
        <input type="button" value="loadImage" onclick="loadImage('a.jpg', imgLoaded)" />
    </body>
</html>
